The objective of this open-label, randomized, two-period, crossover study was to evaluate the oral bioavailability of the Mallinckrodt extended release test capsule formulation of chlorpheniramine polistirex/hydrocodone polistirex compared to an equivalent oral dose of a commercially available extended release oral suspension of chlorpheniramine polistirex/hydrocodone polistirex (Tussionex® Pennkinetic® Extended Release Oral Suspension, Celltech Pharmaceuticals, Inc.) in a test group of healthy subjects under fasting conditions.